Effect Of Built-in Electric Field Research Articles

Synergistic Regulation of Built-In Electric Field and Interface Effect to Enhance the Reaction Kinetics and Stability of Lithium-Ion Batteries

Synergistic Regulation of Built-In Electric Field and Interface Effect to Enhance the Reaction Kinetics and Stability of Lithium-Ion Batteries

Simultaneous photocatalytic removal of tetracycline and hexavalent chromium by BiVO4/0.6CdS photocatalyst: Insights into the performance, evaluation, calculation and mechanism

In this study, a novel Z-scheme heterojunction on bismuth vanadium/cadmium sulfide (BiVO4/0.6CdS) was developed and evaluated for simultaneous photocatalytic removal of combined tetracycline (TC) and hexavalent chromium Cr(Ⅵ) pollution under visible light. Based on the analysis of intermediate products and theoretical calculation, the property of the intermediate products of TC degradation and the effect of built-in electric field (IEF) of composite materials on photo-generated carrier separation were illustrated. According to the experiments and evaluation results, the performance of BiVO4/0.6CdS is higher than CdS 2.83 times and 4.82 times under the visible light conditions, with the aspect of simultaneous oxidizing TC and reducing Cr(Ⅵ), respectively. The catalyst has a faster removal rate in the binary composite pollution system than the single one. Therefore, the photocatalytic degradation of TC using BiVO4/0.6CdS can reduce the toxic effect of TC on the environment. The aforementioned evaluation provides a new design strategy for Z-scheme heterojunction to simultaneous photocatalytic degradation of composite organic and inorganic pollutants.

Tailoring Built-In Electric Field in a Self-Assembled Zeolitic Imidazolate Framework/MXene Nanocomposites for Microwave Absorption.

Heterointerface engineering, which plays a pivotal role in developing advanced microwave-absorbing materials, is employed to design zeolitic imidazolate framework (ZIF)-MXene nanocomposites. The ZIF-MXene composites are prepared by electrostatic self-assembly of negatively charged titanium carbide MXene flakes and positively charged Co-containing ZIF nanomaterials. This approach effectively creates abundant Mott-Schottky heterointerfaces exhibiting a robust built-in electric field (BIEF) effect, as evidenced by experimental and theoretical analyses, leading to a notable attenuation of electromagnetic energy. Systematic manipulation of the BIEF-exhibiting heterointerface, achieved through topological modulation of the ZIF, proficiently alters charge separation, facilitates electron migration, and ultimately enhances polarization relaxation loss, resulting in exceptional electromagnetic wave absorption performance (reflection loss RLmin = -47.35 dB and effective absorption bandwidth fE = 6.32 GHz). The present study demonstrates an innovative model system for elucidating the interfacial polarization mechanisms and pioneers a novel approach to developing functional materials with electromagnetic characteristics through spatial charge engineering.

Synergistic effect of donor-acceptor structure and built-in electric field in hollow-spherical carbon nitride homojunction towards effective charge transfer and excellent photocatalytic hydrogen evolution performance

Polymeric carbon nitride (PCN) is regarded as a most promising photocatalyst, but the severe recombination of electron-hole pairs restrains its photocatalytic performance. Herein, a carbon nitride gradient homojunction with donor–acceptor (D-A) structure was successfully synthesized. The D-A structure promoted the electron delocalization, while gradient K intercalation helped establish a strong internal electric field from the interior to the surface. They synergistically inhibited the recombination of electron-hole pairs and led to fast charge transfer and much enhanced photocatalytic hydrogen evolution (PHE) performance. This work developed a novel method to promote the charge carrier transfer in carbon nitrides, which could provide a new perspective for the design and development of carbon nitride-based homojunctions in the application of PHE.

Nanoarchitectonics toward Full Coverage of CdZnS Nanospheres by Layered Double Hydroxides for Enhanced Visible-Light-Driven H2 Evolution.

Nanoarchitectonics of semiconductors shed light on efficient photocatalytic hydrogen evolution by precisely controlling the surface microenvironment of cocatalysts. Taking cadmium zinc sulfide (CZS) nanoparticles as a target, the spontaneous modifications are conducted by interactions between surface Cd2+ /Zn2+ atoms and thiol groups in thioglycolic acid. The capping ligand impacts the semiconductor surface with a negative electronic environment, contributing to the full coverage of CZS by nickel-cobalt hydroxides (NiCo-LDHs) cocatalysts. The obtained core-shell CZS@NiCo-LDHs, possessing a shell thickness of ≈20nm, exhibits a distinguished topology (SBET =87.65m2 g-1 ), long surface carrier lifetime, and efficient charge-hole separation. Further photocatalytic hydrogen evaluation demonstrates an enhanced H2 evolution rate of 18.75mmolg-1 h-1 with an apparent quantum efficiency of 16.3% at 420nm. The recorded catalytic performance of the core-shell sample is 44.6 times higher than that of pure CZS nanospheres under visible light irradiation. Further density functional theory simulations indicate that sulfur atoms play the role of charge acceptor and surface Ni/Co atoms are electron donors, as well as a built-in electric field effect can be established. Altogether, this work takes advantage of strong S affinity from surface metal atoms, revealing the interfacial engineering toward improved visible-light-driven photocatalytic hydrogen evolution (PHE)activity.

Unveiling the potential of two-dimensional Janus ScXAlY (X/Y=P, As) materials and heterostructures in visible-light-driven photocatalytic water splitting

Two-dimensional (2D) material with Janus-induced built-in electric field, has become a research focus arising from their characteristic physical and chemical properties, especially in photocatalytic water splitting applications. Herein, we introduce a novel family of 2D Janus materials, named ScXAlY (X/Y = P, As), and prove these Janus materials and their heterostructures as promising water splitting photocatalytic candidate materials, leveraging first-principles calculations. All Janus structures and heterostructures exhibit strong dynamical, thermal, and mechanical stabilities. These 2D Janus ScXAlY materials possess wide band gaps, excellent electronic carrier mobilities, and appropriate band edges to facilitate overall water splitting, and moreover can attain Janus-induced built-in electric field effect. Interestingly, the heterostructures (ScXAlY/ScXAlY) surpass the individual materials in performance, demonstrating enhanced solar-to-hydrogen (STH) efficiencies (>30 %) and increscent electrostatic potential differences (>0.85 eV). Furthermore, they show comprehensive photoabsorption across the visible light spectrum, with peak absorptions more than doubling those of the single materials. These heterostructures also display effective spatial separation of electrons and holes which can further boosting their photocatalytic capabilities. Our findings underscore the potential of Janus ScXAlY materials and their heterostructures, in facilitating visible-light-driven photocatalytic water splitting, showcasing a promising avenue for advancement in this burgeoning field.

Interfacial charge redistribution to promote the catalytic activity of Vs-CoP-CoS2/C n-n heterojunction for oxygen evolution

Modulating surface charge redistribution based on interface and defect engineering has been considered as a resultful means to boost electrocatalytic activity. However, the mechanism of synergistic regulation of heterojunction and vacancy defects remains unclear. Herein, a Vs-CoP-CoS2/C n-n heterojunction with sulfur vacancies is successfully constructed, which manifests superior electrocatalytic activity for oxygen evolution, as demonstrated by a low overpotential of 170 mV to reach 10 mA/cm2. The experimental results and density functional theory calculations testify that the outstanding OER performance of Vs-CoP-CoS2/C heterojunction is owed to the synergistic effect of sulfur vacancies and built-in electric field at n-n heterogeneous interface, which accelerates the electron transfer, induces the charge redistribution, and regulates the adsorption energy of active intermediates during the reaction. This study affords a promising means to regulate the electrocatalytic performance by the construction of heterogeneous interfaces and defects, and in-depth explores the synergistic mechanisms of n-n heterojunction and vacancies.

The built-in electric field and spin-pinning effect in BiVO4/Fe0.4Co0.6Se2/Co(Fe)OxHy for enhanced photoelectrochemical water oxidation

Photoelectrocatalytic water splitting is a promising method for producing green and clean energy. In this research, a three-layer composite photoanode BiVO4/Fe0.4Co0.6Se2/Co(Fe)OxHy, named as M@BFOH5, is prepared by a in situ electro-oxidation reconstitution and magnetization method. Through constructing a p-n heterojunction BiVO4/Fe0.4Co0.6Se2, a built-in electric field is formed to accelerate electron transfer in the cross-layer channels. The spin-pinning effect caused by ferromagnetic semiconductor Fe0.4Co0.6Se2 induce spontaneous polarization in the ultra-thin Co(Fe)OxHy layer, which is favorable for conductivity of the passivation layer (Co(Fe)OxHy). The results demonstrate the exceptional oxygen reduction reaction performance of M@BFOH5, achieving a photocurrent density of 4.99 mA cm−2 at 1.23 V in comparison to the reversible hydrogen electrode. This represents an enhancement of 3.1 and 1.37 times over BiVO4 and BFOH5, respectively. Additionally, the charge separation and charge injection efficiencies significantly increased to 92.44 % and 82.68 %, correspondingly. This subtle catalyst is designed to help accelerate oxygen reduction reaction.

Built-in electric field and hydrostatic pressure effects on exciton states in a wurtzite (In,Ga)N/GaN coupled double quantum well

Built-in electric field and hydrostatic pressure effects on exciton states in a wurtzite (In,Ga)N/GaN coupled double quantum well

A Co2N/CoP p-n junction with modulated interfacial charge and rich nitrogen vacancy for High-Efficiency water splitting

In-depth study the regulation mechanism of p-n heterogeneous interface and vacancy defects on electrocatalytic performance remains a great challenge. Herein, a nitrogen-vacancy-rich Co2N/CoP@CC p-n junction with enhanced HER and OER activities has been successfully developed. In detail, the Co2N/CoP@CC delivers HER activity comparable to the commercial Pt/C catalyst, as demonstrated by the ultra-low overpotential of 44 mV, and also shows excellent OER activity with an overpotential as low as 227 mV at 10 mA cm−2 in alkaline medium. Meanwhile, the water splitting potential of 1.5 V for the Co2N/CoP@CC heterojunction at 10 mA cm−2 is also achieved. DFT theoretical calculations indicate the outstanding electrocatalytic activity of Co2N/CoP@CC may be attributed to the synergy effect of abundant nitrogen vacancies and built-in electric field induced by rich p-n interfaces, which can effectively promote electron transfer, realize charge redistribution, adjust the adsorption/desorption free energy of the intermediates, and thus significantly enhancing the electrocatalytic activity.

Full-spectrum broad-spectrum degradation of antibiotics by BiVO4@BiOCl crystal plane S-type and Z-type heterojunctions

Based on the poor full-spectrum broad-spectrum catalytic activity of the exposed crystal faces of BiVO4, a photo-deposited crystal plane selectively induce method was used to nucleate the strong reduction-capable BiOCl on BiVO4 (010) crystal planes in the heterogeneous phase and the OVs-BiOCl on BiVO4 (110) crystal planes in the homogeneous phase. The core–shell BiVO4@BiOCl crystal plane S-type and Z-type heterojunction photocatalysts were prepared. Under the synergistic effects of the surface heterojunction built-in electric field, the interfacial electrostatic built-in electric field, the inter-heterojunction polarization charge transfer and the Localized Surface Plasmon Resonance (LSPR) effect of oxygen vacancies, the BiVO4@BiOCl exhibits strong broad-spectrum degradation ability over the entire spectral range and exhibits excellent degradation cycle stability. The degradation rates of BiVO4@BiOCl for TC are 90.32%/71.17%, the TOC removal rates are 74.07%/57.81% and degradation efficiencies of CIP, BHA, Phenol, BPA and Coumarin are 49.36 ∼ 71.32%/37.88% ∼ 62.86%, respectively, after Vis/NIR light irradiation, respectively. It also shows good degradation performance of the mixed antibiotic solutions. This study offers a feasible research proposal for surface heterogeneous crystalline facet selective induction of oxygen vacancies to induce the enhanced full-spectrum broad-spectrum degradation performance of heterojunction photocatalysts for the application of environmental purification.

Synergistic effect of oxygen vacancies and built-in electric field in GdCrO3/BiVO4 composites for boosted photocatalytic reduction of nitrate in water

As a promising approach for nitrate nitrogen removal in water, photocatalysis required sufficient photogenerated charges to achieve a high photocatalytic efficiency. Herein, a novel GdCrO3/BiVO4 composite was prepared by the solid-state combustion method combined with hydrothermal treatment. The synergistic effect of oxygen vacancies introduced by chemical reduction method and built-in electric field formed in GdCrO3/BiVO4 heterostructures suppressed the charge recombination, which eventually improved the photocatalytic activity. Effects of photocatalyst composition, HCOOH dosage and oxygen vacancy concentration on photocatalytic activity were investigated. It was found that 0.30-GdBiOVs composites exhibited highest photocatalytic activity with nitrate removal ratio of 97.05% and N2 selectivity of 92.76% in 40 min. Moreover, end-products of nitrate nitrogen elimination and stability of photocatalysts were revealed. The existences of oxygen vacancies and built-in electric field were confirmed by EPR and HRTEM analyses. Ultimately, the possible mechanisms of nitrate nitrogen elimination were clarified.

Nickel sulfide/nickel phosphide heterostructures anchored on porous carbon nanosheets with rapid electron/ion transport dynamics for sodium-ion half/full batteries

Nickel-based materials have been extensively deemed as promising anodes for sodium-ion batteries (SIBs) owing to their superior capacity. Unfortunately, the rational design of electrodes as well as long-term cycling performance remains a thorny challenge due to the huge irreversible volume change during the charge/discharge process. Herein, the heterostructured ultrafine nickel sulfide/nickel phosphide (NiS/Ni2P) nanoparticles closely attached to the interconnected porous carbon sheets (NiS/Ni2P@C) are designed by facile hydrothermal and annealing methods. The NiS/Ni2P heterostructure promotes ion/electron transport, thus accelerating the electrochemical reaction kinetics benefited from the built-in electric field effect. Moreover, the interconnected porous carbon sheets offer rapid electron migration and excellent electronic conductivity, while releasing the volume variance during Na+ intercalation and deintercalation, guaranteeing superior structural stability. As expected, the NiS/Ni2P@C electrode exhibits a high reversible specific capacity of 344 mAh g−1 at 0.1 A g−1 and great rate stability. Significantly, the implementation of NiS/Ni2P@C//Na3(VPO4)2F3 SIB full cell configuration exhibits relatively satisfactory cycle performance, which suggests its widely practical application. This research will develop an effective method for constructing heterostructured hybrids for electrochemical energy storage.

InGaAs-based Gunn light emitting diode

We report an n-type In0.53Ga0.47As based Gunn light emitting diode operated at around 1.6 μm. The device structure comprises of an n-type In0.53Ga0.47As epilayer with a thickness of 5 μm grown by Metal Organic Vapour Phase Epitaxy (MOVPE) on a semi-insulating InP substrate and fabricated in a planar architecture with a stepped structure at anode side to suppress the destructive effect of high built-in electric field in propagating Gunn domain. Gunn diode is operated under pulsed voltage with a pulse width of 60 ns and pulse duration of 4.5 ns to keep the duty cycle as low as 0.0013%. The Gunn oscillations with an 1 ns period are observed at around 4.1 kV/cm, which corresponds to the electric field threshold of Negative Differential Resistance (NDR). The light emission at around 1.6 μm also starts at the threshold electric field of the NDR region (E = 4.2 kV/cm) of the current-voltage curve, and the emission intensity increases drastically with increasing applied electric field. The observed light emission at NDR threshold electric field where Gunn oscillations appear on the voltage pulse is attributed to the impact ionisation process occurring in the current domains along the sample, which generates excess carriers to initiate the band-to-band recombination in In0.53Ga0.47As.

Implanting Built-In Electric Field in Heterometallic Phthalocyanine Covalent Organic Frameworks for Light-Assisted CO 2 Electroreduction

Open AccessCCS ChemistryRESEARCH ARTICLES29 Dec 2022Implanting Built-in Electric Field in Hetero-metallic Phthalocyanine Covalent Organic Frameworks for Light-assisted CO2 Electroreduction Xi Tian, Xin Huang, Jing-Wen Shi, Jie Zhou, Can Guo, Rui Wang, Yi-Rong Wang, Meng Lu, Qi Li, Yifa Chen, Shun-Li Li and Ya-Qian Lan Xi Tian Google Scholar More articles by this author , Xin Huang Google Scholar More articles by this author , Jing-Wen Shi Google Scholar More articles by this author , Jie Zhou Google Scholar More articles by this author , Can Guo Google Scholar More articles by this author , Rui Wang Google Scholar More articles by this author , Yi-Rong Wang Google Scholar More articles by this author , Meng Lu Google Scholar More articles by this author , Qi Li Google Scholar More articles by this author , Yifa Chen Google Scholar More articles by this author , Shun-Li Li Google Scholar More articles by this author and Ya-Qian Lan Google Scholar More articles by this author https://doi.org/10.31635/ccschem.022.202202519 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Strategy that enables introducing bimetallic active sites is desired for the exploration of light-sensitive covalent-organic-frameworks (COFs) based electrocatalysts in light-assisted CO2-electroreduction. Herein, salphen-pockets have been implanted into phthalocyanine-based COFs through the elaborate design of structure-struts and thus-produced NiPc-DFP-M COF (M = Ni and Co) possess the advantages of controllably bimetallic centers with different coordination-environments, outstanding light-sensitivity, and built-in electric-field effect that can be successfully applied in light-assisted CO2 electroreduction. Notably, the optimally hetero-metallic NiPc-DFP-Co COF presents a high FECO (~100%) in a wide potential-range of -0.7 V to -1.1 V and ~70% energy-efficiency (-0.7 V) under light-irradiation, which is superior to mono-/homo-metallic COFs and under dark conditions. The high performance can be ascribed to the synergistic effect of NiPc and Co-salphen pockets that can largely reduce the rate-determining energy-barrier and enhance the electron-density to boost the light-assisted activity as supported by DFT-calculations. Download figure Download PowerPoint Previous articleNext article FiguresReferencesRelatedDetails Issue AssignmentVolume 0Issue jaPage: 1-11 Copyright & Permissions© 2022 Chinese Chemical Society Downloaded 0 times PDF downloadLoading ...

Photocatalytic oxygen reduction reaction over copper-indium-sulfide modified polymeric carbon nitride S-scheme heterojunction photocatalyst

Photocatalytic oxygen reduction reaction (ORR) to produce hydrogen peroxide (H2O2) has been regarded as an environmentally friendly strategy compared with the anthraquinone oxidation process. Superior photocatalytic activity strongly depends on the efficient separation of charge carriers. Herein, the step-scheme (S-scheme) heterojunction catalysts (CuInS2/PCN) over copper-indium-sulfide (CuInS2) modified polymeric carbon nitride (PCN) were constructed via in-situ low-temperature hydrothermal method. The difference of Fermi levels between PCN and CuInS2 promoted the spontaneously charge transfer directing from CuInS2 to PCN, leading to the construction of built-in electric field at the interface. The S-scheme heterojunction was successfully formed on the effect of built-in electric field, whereby offered a new charge transfer route resulting in efficient migration and strong redox abilities of photogenerated electrons and holes. The optimized H2O2 yield of 3CuInS2/PCN (1247.6 µmol·L−1·h−1) was nearly 11.6 and 16.0 times higher than PCN (107.4 µmol·L−1·h−1) and CuInS2 (78.0 µmol·L−1·h−1), respectively, and the apparent quantum yield (AQY) for H2O2 production over 3CuInS2/PCN reached 16.0 % at 420 nm. Photo-irradiated Kelvin probe force measurement revealed the S-scheme charge transfer mechanism between PCN and CuInS2. This work offers a facile surface modification method for the design of photocatalyst in photocatalytic selective oxygen reduction reaction.

High-efficiency photocathodic protection performance of novel MnIn2S4/TiO2 n-n heterojunction films for Q235 carbon steel in chloride-containing simulated concrete pore solution

In this work, the n-type TiO2 nanotube film was modified successfully by n-type MnIn2S4 nanoparticles with one-step hydrothermal method, and a novel MnIn2S4/TiO2 heterojunction material with excellent photoelectrochemical properties was constructed firstly. Owing to the modification, the light response range of MnIn2S4/TiO2 nanocomposites was extended to the visible light region. Benefiting from the presence of type II n-n heterojunction with built-in electric field effects in the nanocomposites, the photogenerated carriers recombination rate decreased significantly. In addition, the photocathodic protection effects of MnIn2S4/TiO2 (MIS/T) photoanodes on Q235 carbon steel (Q235 CS) immersed in simulated concrete pore solution containing chloride were investigated. Under visible light irradiation, the cathodic protection current density of MIS/T-2 photoanode was found to be more than 30 μA/cm2 and over 10 times that of T photoanode. The MIS/T-2 photoanode has good long-term photochemical stability and maintains excellent photocathodic protection effect on Q235 CS (OCP value are about - 870 mV (vs. SCE)) under visible light irradiation. The amount of MnIn2S4 nanoparticles deposited on the TiO2 film could affect the photoelectrochemical properties of MnIn2S4/TiO2 n-n heterojunctions and an appropriate number of the nanoparticles, corresponding to the best cathodic protection performance was revealed.

Construction of Glutinous Rice Potpourri-like MOTT−Schottky Ni/CeO2 Heterojunction Nanosheets for Robust Electrochemical Water Reduction

The development of efficient non-precious metal electrocatalysts through more economical and safe methods is consistent with the goals of sustainable development and accelerating the achievement of “carbon neutrality” in the 21st century but remains potentially challenging. Mott–Schottky heterojunction interfaces generated from metal/semiconductor have been a hot topic of recent research because of the unique built-in electric field effect which allows the preparation of more superior catalysts for water electrolysis. Herein, a glutinous rice potpourri-like Mott–Schottky two-dimensional (2D) nanosheet (abbreviated as Ni/CeO2 HJ-NSs) electrocatalyst composed of metal nickel (Ni) and cerium oxide (CeO2) hetero-nanoparticles was synthesized by a simple and scalable self-assembly and thermal reduction strategy. The experimental results and mechanistic analysis show that the Mott–Schottky heterojunction interface composed of metallic Ni and n-type semiconductor CeO2 with built-in electric field induces the electron redistribution at the interface to accelerate the dissociation of water and the binding of reaction intermediates, thus achieving lower water dissociation energy and more thermoneutral ΔGH* value to expedite the kinetics of the hydrogen evolution reaction (HER). Thus, the prepared Ni/CeO2 HJ-NSs exhibit excellent HER catalytic performance in 1 M KOH electrolyte with an overpotential of only 72 mV at 10 mA cm−2, as well as a moderate Tafel slope of 65 mV dec−1 and an extraordinary long-term stability over 50 h, laying a solid foundation for further in-depth investigation. The synthesis of splendid electrocatalysts by exploiting the metal/semiconductor interface effect provides an innovative way for the future generation of Mott–Schottky-based heterostructures with three or more heterocompositions with two or more heterojunction interfaces.

Photoelectrocatalytic degradation of sulfamethoxazole over S–Scheme Co3Se4/BiVO4 heterojunction photoanode: An experimental and density functional theory investigations

We have carried out comprehensive experimental and density functional theory simulations of Co3Se4/BiVO4 heterojunction to understand the relationship between interface and enhanced photocatalytic activity. This study demonstrates the photoelectrochemical degradation of sulfamethoxazole (SMX) with a photoanode developed based on S–Scheme heterojunction. The difference in the energy levels of the band gaps and conduction bands of BiVO4 and Co3Se4 makes them suitable semiconductors for the fabrication of an S–Scheme heterojunction. The BiVo4/Co3Se4 composite is prepared by solvothermal method and characterized using X–ray diffraction (XRD), field emission–scanning electron microscopy (FE–SEM), transmission electron microscopy (TEM), Energy Dispersive X–Ray Analysis (EDX), Ultraviolet–Visible Diffuse Reflectance Spectroscopy (UV–DRS). The photoelectrochemical properties of the fabricated photoanode are studied using Electrochemical impedance spectroscopy (EIS), Mott–Schottky, and photocurrent response. The UV–DRS spectra show an improved band gap (1.88 eV) for the composite in comparison with pristine BiVO4 (2.39 eV). The XRD patterns reveal the presence of monoclinic phases of BiVO4 and Co3Se4 in the composite. This is further confirmed by the microscopic studies that show the surface coating of Co3Se4 on BiVO4. The composite photoanode shows improved photocurrent density and low charge transfer resistance in comparison with the pristine semiconductors. Theoretical calculations reveal charge redistributions at the interface between Co3Se4 and BiVO4. Furthermore, the density of states, Bader charge and electrostatic potential drop reveals that the synergistic effect of built-in electric field directed from the BiVO4 surface to the Co3Se4 surface facilitates the efficient separation of charge carriers in the Co3Se4/BiVO4 interface and thus prevents carrier recombination rate. This provides the composite with the capacity to effectively degrade SMX with improved efficiency. At optimum conditions, the SMX degradation efficiency reached 75% with a rate constant of 0.0115 min–1. The holes majorly facilitate the degradation of SMX, as revealed by the scavenger study. Comparative studies indicate that photoelectrocatalytic contributions supersede photocatalytic and electrocatalytic contributions.

Unveiling the enhancement essence on Li2S deposition by the polarized topological β-polyvinylidene fluoride: Beyond built-in electric field effect

Electric field from ferroelectric materials was often applied to energy-storage devices to enhance their electrochemical reaction kinetics via the electrostatic interaction. However, traditional ferroelectric materials are difficult to be used commercially for their insulation. Herein, we elucidate a novel strategy to introduce the electrostatic interaction by polarizing the polyvinylidene fluoride (PVDF) binder used in the C/S cathodes for lithium-sulfur batteries. In particular, we show both experimentally and theoretically how an external electric field from β-phase PVDF induces unprecedented performance and stabilities. Density functional theory calculation results indicate that the polarized topological β-phase PVDF possesses not only an strong built-in electric field and an improved conductance that benefits both the deposition of LiPSs and the transport of Li+ ions, but also an enhanced adsorption capability to polysulfide ions. As a result, the specific capacity was improved by over 60 %, the rate capability (from 0.1 to 2.0 C) was enhanced by 138 %, and the capacity decay rate (1000 cycles at 1.0 C) largely decreases from 0.059 % to 0.038 % per cycle. Besides, the enhancement mechanism of Li2S deposition by electrostatic interaction has also been explored. This research would provide some new insight into the ferroelectric enhanced design of high-performance energy-storage devices.